Derek Parfit's Theory Of Personal Identity

Derek Parfit is a British philosopher who specialises in problems of personal identity and he proposes that we separate the notions of identity and survival. He is one of the most prominent philosophers in the struggle to define the self. Parfit’s 1971 essay “Personal Identity” targets two common beliefs which are central to the earliest conversations about personal identity. The first belief is about the nature of personal identity; all questions regarding this must have an answer. Between now and any future time, it is either the case that “I shall exist or I shall not”. Identity is simply all-or nothing. The second belief that he targets regards the importance of personal identity; important matters involving survival, memory and responsibility.

‘Will I survive?’, ‘Am I the same person?’, ‘Will there be some person alive who is the same person as me?’ (Parfit, 1971, p.9) these are all questions that must be answered in order to determine ones survival or future responsible actions. Parfit, however, argues that these beliefs are false or mistaken as such. He has three fundamental arguments; 1. He rejects both the physical and soul theories of the self. 2. He asserts that personal identity is not what matters for the survival of the self. 3. He claims that it is Relation R or connectedness that matters for the survival of the self. (Johnson, 2007, p.2)
Throughout his essay, Parfit relies on the results of certain thought experiments particularly ones put forward by fellow moral philosopher, metaphysician and philosophical logician David Wiggins. He puts a large amount of emphasis on one particular case, Wiggins’ case of fission. This case involves a situation where a man’s brain is split in two while there are two waiting brainless bodies. Each hemisphere of the man’s brain is then separately transplanted into the two waiting bodies. The aim of this case for Parfit is to establish whether or not the man survives. It has been proven

In Wiggins’ case of fission he undermines the belief that all questions of personal identity must have answers. The belief when asked in response to brain division is found implausible. According to Parfit, ‘If all the possible answers are implausible, it is hard to decide which of them is true, and hard even to keep the belief that one of them must be true’. (1971, p.8) He also undermines the second belief that personal identity plays a part in survival. Wiggins’ case shows that you may not have identity but you may have everything you need for survival. Parfit therefore argues that the relation of ‘Fred’ to each of the resulting people is not a relation of identity but does contain ‘all that interests us - all that matters - in any ordinary case of survival’. (1971,